Wireless mobile communication technology uses various standards and protocols to transmit data between a node (e.g., a transmission station) and a wireless device (e.g., a mobile device). Some wireless devices communicate using orthogonal frequency-division multiple access (OFDMA) in a downlink (DL) transmission and single carrier frequency division multiple access (SC-FDMA) in an uplink (UL) transmission. Standards and protocols that use orthogonal frequency-division multiplexing (OFDM) for signal transmission include the third generation partnership project (3GPP) long term evolution (LTE), the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard (e.g., 802.16e, 802.16m), which is commonly known to industry groups as WiMAX (Worldwide interoperability for Microwave Access), and the IEEE 802.11 standard, which is commonly known to industry groups as WiFi.
In 3GPP radio access network (RAN) LTE systems, the node can be a combination of Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node Bs (also commonly denoted as evolved Node Bs, enhanced Node Bs, eNodeBs, or eNBs) and Radio Network Controllers (RNCs), which communicates with the wireless device, known as a user equipment (UE). The downlink (DL) transmission can be a communication from the node (e.g., eNodeB) to the wireless device (e.g., UE), and the uplink (UL) transmission can be a communication from the wireless device to the node.
In LTE, data can be transmitted from the UE to the eNodeB via a physical uplink shared channel (PUSCH). The PUSCH can carry scheduled data traffic and possible control signaling. The PUSCH can be carried in subframes of a radio frame. A one millisecond (ms) subframe can allow a one ms scheduling interval (or transmission time interval (TTI)). Uplink coverage may be limited by a maximum transmission power of the wireless device. In some situations, a voice-over-internet protocol (VoIP) packet, for example, cannot be transmitted in a one ms subframe with an acceptable error rate. One solution to transmit a VoIP packet is to segment the VoIP packet at higher layers to allow the VoIP packet to be transmitted over several subframes. However, such segmentation can result in additional signaling overhead for each segment (including resource allocation signaling and hybrid automatic repeat request (hybrid ARQ or HARQ) acknowledgement signaling). A technique for improving uplink VoIP coverage at a cell edge can be to use TTI bundling, where a single transport block (TB) from a medium access control (MAC) layer is transmitted in multiple consecutive subframes, with one set of signaling messages (e.g., HARQ acknowledgement feedback) for the whole uplink transmission. For example, the PUSCH can allow groups of 4 TTIs to be bundled together in addition to the single one ms TTI.
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.